Coronary bifurcation lesions are encountered in approximately 20% of the >1.25 million percutaneous coronary interventions (PCI) performed annually. Even in the drug-eluting stent era, the complexity of these lesions and technical challenges in their treatment result in long term major adverse cardiac event, target lesion revascularization, restenosis, and stent thrombosis rates that are far greater than in non-bifurcating lesions. Further complexities arise when treating unprotected left main coronary artery bifurcating lesions, as complications may be catastrophic. Optical coherence tomography (OCT) is commonly employed to guide interventional strategies following a provisional stenting (i.e., stenting of the main vessel) and, in particular, guide wire recrossing to correct for a jaild side branch. Despite the high in-plane resolution of OCT (10-20 m), which is the only intravascular imaging modality that allows for visualization of stent struts, poor axial resolution (200 m) prevents a complete visualization of the deployed stent and understanding of the spatial relationship with surrounding target bifurcation lesion to guide optimal interventional treatment strategies. To overcome the significant shortcoming of current techniques, we propose to develop an algorithm to visualize the complete 3D stent structure with respect to the target bifurcation lesion. Our approach will use advanced image processing and shape memory matching techniques to develop an algorithm to automatically reconstruct, at a high-resolution (~5 m), the complete 3D deployed stent geometry by fusing OCT and micro- computed tomography (CT) imaging data. (Aim 1). The algorithm will be validated in patient-specific coronary bifurcating lesion phantoms. To examine the utility and feasibility of the algorithm in the clinical environment, we will employ the developed reconstruction technique on clinical OCT data to assess the post-provisional stent geometry and surrounding target bifurcation lesion (Aim 2). Successful completion of the proposed research will allow for a complete and clear understanding of the deployed stent from only intravascular OCT imaging data to guide clinical treatment strategy. Furthermore, the proposed research will form the foundation for future investigations of truly patient-specific stent mechanical modeling towards development of lesion- specific stenting strategies.